Various accessories have been developed for mobile telephones to improve their usability. One of these is an HF set for a car that has a cradle for receiving a mobile telephone. The cradle comprises an interface for charging the mobile telephone and another interface for coupling an external speaker and microphone (HF equipment) to the mobile telephone when placed in the cradle. This enables the HF operation and easy charging of the mobile telephone. More recently, the talk and standby times of mobile telephones have increased so that charging is not usually required during a car journey. Therefore, many individuals have considered HF sets to be unnecessary in car. However, if a mobile telephone is kept in a pocket or attached to a belt, answering mobile telephone calls can be inconvenient.
Wireless Bluetooth HF-sets have been developed to provide an easy connection of a mobile telephone with the HF-set. A mobile telephone brought into a car can connect to the HF-set from a pocket or a briefcase by means of Low-Power Radio Frequency (LPRF) waves. For example, Parrot has presented in their press release a Bluetooth enabled car HF set Parrot CK3000. According to the press release, this kit is based on Parrot's technology and powered by Parrot's Chip “Parrot3”, which provides voice recognition. The user can place a call with his phone in his pocket or briefcase.